Practice ammunition



June 20, 1967 H. STADLER ETAL 3,326,133

ACTICE Filed Sept. 5, 1964 INVENTORS.

HANS STADLER THOMAS SCHlNNERER HANS UMBACH GUNTHER MARONDEL duh, ATTORNEY United States Patent 2 Claims. (or: lea-92.7

The present invention relates to practice ammunition, and moreparticularly to target practice ammunition made of thermo-plasticmaterial.

With the use of target practice cartridges in shells or bullets, whichare made in the prior art of metallic materials, there exists the dangerthat the shells or bullets upon impact on hard objects of stone, metalor the like, are deflected or even reflected, which representsespecially with short target distances a considerable danger for thesharp-shooter and also for other by-standers disposed in proximitythereto, such as for example observers. Suitable solutions have beensought already for some time to eliminate this disadvantage.

For target practice ammunition with rim ignition a solution has alreadybeen found in that the shells were made or compressed of lead oxide orgranulated lead. These shells formed of a large number of minuteparticles have the property that upon impact on a thin steel diskarranged behind the target they readily decompose and disintegrate intothese smallest particles and accordingly are safe against any possibledeflection, richocheting and/ or reflection.

In the course of the increasing use of plastic materials, one seeks moreand more also in the manufacture of ammunition to utilize in lieu of theexpensive metals, the considerably more inexpensive plastic materials.In that connection, a so-called plastic tnaining ammunition is alreadyknown of which the shell consists of a thermo-plastic material and whichis of correspondingly light weight. In addition to the advantages of lowcost and of a light weight, this type of prior art plastic ammunition,however, also has the significant disadvantage that is suitable only fora single shot or single round usage but not, in contrast, for use inautomatic weapons or arms because, owing to the small weight of theshell, no automatic function of the weapon or arm is realizable withoutchanging the breech mechanism and certain other parts of the weapon.

The aim of the present invention is now to create a target practiceammunition made of plastic material, preferably of thermo-plasticmaterial, which assures in its use the proper operation of automaticweapons but as to the rest exhibits the properties of the aforementionedgranulated lead shells or the like that decompose and disintegratereadily and completely upon impact on the hard targets and objects inparticular. According to the present invention, with a view to achievethis aim, it is proposed to add to or incorporate in the plasticmaterial by conventional means fibers, chips, splinters, shavings,granulated materials, or powdered materials of heavy metal or heavypigments whereby the ratio of plastic to metal or pigment amounts tobetween about 40:60 and 20:80. Tests have demonstrated that such ashell, which may be readily manufactured without difiiculty in the usualway of the injection moulding or transfer molding processes, possessesin addition to a sufficiently large weight assuring proper operation ofthe automatic weapon or arm, also the property of easy disintegrationupon impact on a target which is completely surprising insofar as thetenacity and toughness of the plastic material would lead one to expectthat the shell, upon impact on such an obstacle, would only be deformedbut would not decompose and disintegrate.

It is proposed in an appropriate further development of the presentinvention to construct the shell with a flattened tip in a planeperpendicular to the shell axis whereby, on the one hand, thecompression and therewith the readiness to disintegrate upon impact isincreased and, on the other-as is generally desired with target practicecartridge shell-the flight distance of the shell is reduced by anincrease of the air resistance coefiicient thereof. The shell itself isthereby constructed with an essentially cylindrical shank portion andtapers in the direction toward its forward end with a casing surfaceconvexly curved toward the outside. An increase in the disintegrationreadiness of the shell can still further be achieved in that a central,preferably conical aperture is provided at the forward end thereof.

A good disintegration capability and a high air resistance coefficienthowever, is also assured by the arrangement of a central, preferablyconical aperture at the rear shell end which extends substantially overthe entire cylindrical area of the shell. According to one proposal ofthe present invention provision is made to construct the casing surfaceof the aperture slightly convexly curved toward the shell axis. Withsuch a construction of the shell, the propellent gases penetrating intothe aperture effect a particularly good seal between the shell and thebarrel. Additionally, the center of gravity of the shell is displaced bythe aperture, similarly as with an arrow, very far towards the forwardend thereof which has a very favorable effect on the flight stability ofthe shell.

If the shell is constructed cylindrically over the entire lengththereof, then there exists the possibility to selectively fire the shellwith one or the other end in front. If one of the ends is therebyconstructed as a plane surface perpendicular to the shell axis and theother end is provided with a central aperture, then in case of a firingof the shell with the aperture disposed in front thereof, there resultsagain a particularly good disintegration capacity whereas in case of afiring of the shell with the plane end face disposed in front thereof,there is obtained a type of lip seal at the shell end and therewith agood adaptation of the walls of the shell rear part to the barrel.

Accordingly, it is an object of the present invention to provide atarget practice ammunition which eliminates the aforementionedshortcomings and drawbacks encountered with the prior art constructionsyet permits use of plastic materials.

Another object of the present invention resides in the provision of atarget practice shell which may be made of plastic material therebyresulting in a considerable reduction in the manufacturing cost withoutincrease in danger to personnel utilizing the same.

Still a further object of the present invention resides in the provisionof a target practice cartridge for shells that is made of athermo-palst-ic material, yet possesses a high capacity to decompose anddisintegrate into minute particles upon impact on a hard object.

A further object of the present invention resides in the provision of aplastic target practice shell that can be used with automatic weaponswithout requiring any change in the automatic firing mechanisms thereof.

A still further object of the present invention resides in the provisionof a plastic shell achieving the aforementioned aims and objects whileat the same time enhancing the flight stability accompanied with areduction of the flight distance.

Still another object of the present invention resides in the provisionof a plastic training practice shell that can be selectively fired witheither end as the leading end thereof.

These and further objects, features and advantages of the presentinvention will become more obvious from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, several embodiments in accordance withthe present invention, and wherein FIGURE 1 is an elevational view of asolid shell in accordance with the present invention provided with planeend faces perpendicular to the shell axis;

FIGURE 2 is an elevational view, partly in cross section, of a modifiedembodiment of a shell in accordance with the present invention, similarto FIGURE 1 but provided with a central aperture in the tip thereof;

FIGURE 3 is an axial longitudinal cross sectional view through a stilfurther modified embodiment of a shell in accordance with the presentinvention, similar to FIGURE 1 but provided with a central aperture inthe rear part thereof, and

FIGURE 4 is an elevational view, partly in cross section, of acylindrical shell in accordance with the present invention provided witha central aperture at one end thereof.

Referring now to the drawing wherein like reference numerals are usedthroughout the various views to designate like parts, and moreparticularly to FIGURE 1, the shell illustrated therein is provided witha cylindrical shank portion 1 and with a tapered end portion 2. Both endfaces 3 and 4 of the shell are constructed as plane surfaces extendingperpendicularly to the shell axis 5. The casing surface 6 of the taperedforward end portion 2 of the shell is curved slightly convexly towardthe outside.

By reason of the flattened forward end, the shell 1 does not penetrateinto the object or target but instead is forcibly stopped and stronglycompressed upon impact on the same, whereby the texture of the shell isbroken down so that the shell, as desired, decomposes and disintegratesinto small and smallest parts. In addition thereto, the flattenedforward end 3 results in a relatively large air resistance coeflicientso that the velocity and flight distance of the shell is considerablyreduced, however, substantially without impairing the flight stabilityof the shell.

According to FIGURE 2 the shell, which corresponds essentially to theshell of FIGURE 1 as regards its shape, is provided at the forward endthereof with a central conical recess 7 which, as shown in this figureof the drawing, is rounded off strongly at the tip 8 thereof but couldalso be constructed so as to be pointed thereat. Of course, it is withinthe scope of the present invention to construct the annular rim surface9 remaining at the forward end of more or less large dimension.

The shell of FIGURE 2 will also fail to bore itself into the target byreason of its relatively large annularly shaped impact surface butinstead is stopped and compressed upon impact. The part of the shellconcentrated within the area of the shell axis is thereby displaced withrespect to the remaining part of the shell in the direction of the shellaxis whereby the texture of the shell again is broken up and the shelldecomposes and disintegrates into small particles. This readiness todecompose is further enhanced in that the trailing parts within the areaof the shell axis in cooperation with the conical aperture 7 effect adeformation of the shell tip into mushroom shape and therewith favor thedisintegration of the shell. Also in this case the relatively largesurface of the forward shell end results in a high air resistancecoefficient so that also with this shell form the velocity and flightdistance of the shell is considerably reduced.

According to FIGURE 3 the shell is provided at the rear end thereof witha very deep recess 10 whereas the forward end is constructed as planeflat surface 3. During the passage of the shell through the barrel ofthe weapon or arm (not shown), the propellent gases penetrating into theaperture 10 effect an abutment of the ring-shaped part 11 against thebarrel walls whereby a good seal between shell and barrel and therewitha complete utilization of the propellent gases is achieved whichpermits, inter alia, to reduce somewhat the propellent charge. However,the good seal between shell and barrel also offers the advantage that apressure of the propellent gases, which is very uniform over the entirecross sectional surface, is established to the rear of the shell andtherewith the intended flight direction is imparted with good accuracyto the shell when leaving the barrel.

If the shell of FIGURE 4 constructed over its entire length as cylinder12, is fired off with its end face 3 extending perpendicularly to theshell axis 5 leading, then by reason of the trapezoidally-shaped recess13, as viewed in cross section, a good seal results again between shelland barrel as with the shell of FIGURE 3. As to the remaindersubstantially similar conditions are obtained also in this case as withthe shell of FIGURE 3. With a firing of the shell in the oppositedirection, that is, with the recess 13 leading, then the behavior of theshell essentially resembles that of the shell of FIGURE 2. Thepossibility to fire the shell of FIGURE 4 in both directions isindicated by the two arrows 14' and 14". 7

While we have shown and described several embodiments in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to a person skilled in the art and we therefore do not wish to belimited to the details shown and described herein but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

The heavy metals and heavy pigments referred to in this specificationwhich may be admixed to the plastic material in any conventional manner,may be of any known types, such as for example lead, iron, copper, theoxides of these metals and mixtures thereof. The plastic shells,preferably thermo-plastic shells, may be realized by any knownconventional molding processes such as injection or transfer molding.

We claim:

1. A target practice cartridge shell made of plastic material,comprising:

a body essentially consisting of plastic material to which is added arelatively heavier material selected from the group consisting ofrelatively heavy metals and relatively heavy pig-ments,

the ratio of plastic to heavy material being between about 40:60 and20:80 percent by weight,

said shell including a substantially cylindrical shank portion,

the rear end of said shell being provided with a central, approximatelyconical recess extending substantially over the entire area of thecylindrical shank portion and being provided with slightly convexlycurved surfaces.

2. A target practice cartridge shell made of plastic material,comprising:

a body essentially consisting of plastic material to which is added arelatively heavier material selected from the group consisting ofrelatively heavy metals and relatively heavy pigments,

5 6 the ratio of plastic to heavy material being between ReferencesCited about 40:60 and 20:80 percent by Weight, UNITED STATES PATENTSsaid shell including a substantially cylindrical shank portion and aforward end portion tapered in the iii E n forward direction andprovided with slightly con- 5 1518920 12/1924 g g i' fif': VeXlY Cum/adsurfaces, 2,593,637 4/1952 We1din 102 41 the rear end of said shellbeing provided with a central,

approximately conical recess extending substantially BENJAMIN A.BORCHELT, Primary Examiner. over the entire area of the cylindricalshank portion 10 FRED C M ATTERN, JR" Examiner. and being provided Withslightly conveXly curved Surfmw R. F. STAHL, Assistant Examiner.

1. A TARGET PRACTIVE CARTIDGE SHELL MADE OF PLASTIC MATERIAL,COMPRISING: A BODY ESSENTIALLY CONSISTING OF PLASTIC MATERIAL TO WHICHIS ADDED A RELATIVELY HEAVIER MATERIAL SELECTED FROM THE GROUPCOINSISTING OF RELATIVELY HEAVY METALS AND RELATIVELY HEAVY PIGMENTS,THE RATIO OF PLASTIC TO HEAVY MATERIAL BEING BETWEEN ABOUT 40:60 AND20:80 PERCENT BY WEIGHT, SAID SHELL INCLUDING A SUBSTANTIALLYCYLINDRICAL SHANK PORTION, THE REAR END OF SAID SHELL BEING PROVIDEDWITH A CENTRAL, APPROXIMATELY CONICAL RECESS EXTENDING SUBSTANTIALLYOVER THE ENTIRE AREA OF THE CYLINDRICAL SHANK PORTION AND BEING PROVIDEDWITH SLIGHTLY CONVEXLY CURVED SURFACES.